Process of annealing metal castings



(No Model.)

J. BVETTS 81; P. C. SGHURZ.

PROCESS OF ANNBALING METAL GASTINGS.

No. 570.919. Patented'Nov'. 10, 1896.

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UNITED STATES PATENT OFFICE.

JAMES EVETTS AND FRANCIS G. SOIIURZ, OF CHICAGO, ILLINOIS.

PROCESS OF ANNEALING M ETAL CASTINGS.

SPECIFICATION forming part of Letters Patent No. 570,919, dated November 10, 1896.

Application filed July 11,1896. Serial No. 598,788. (No specimens.)

To all whom it may concern.-

Be it known that we, JAMES EvE'rTs, a subject of the Queen of Great Britain, and FRAN- oIs C. SCHURZ, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Processes of nealing metal castings, and has for its object to provide means for annealing or decarbonizing metal castings, as, for instance, steel castings, in shorter space of time and with less application of heat than heretofore.

The process of our invention may be generally described as consisting in enveloping the castings to be annealed in fibrous or finelydivided asbestos, which is preferably tightly packed about the castings in a porous or perforated chamber, whereupon the whole is introduced into the annealing-furnace and subjected to an annealing heat for a period of, say, twenty-four hours, when it is withdrawn therefrom and allowed to cool slowly,the process being thus completed. The asbestos may be slightlymoistened when packing to secure flexibility.

The advantages of this system are as follows: The thorough enveloping of the casting in the non-conductingmaterial secures a more even and regular heating; also the asbestos fiber, being in intimate contact with the surfaces of the metal, precludes the possibility of an oxid scale or crust forming on said surfaces, thereby allowing the atmospheric oxygen free and uninterrupted access to the same. By this means thedecarbonizing process is carried on with much greater speed, and the possibility of breaking or cracking the casting is greatly decreased.

The packing of asbestos fiber having once admitted the heat, retains it for a sufficient period of time to insure very gradual cooling of the casting.

The rough scaly surfaces which are present in castings annealed after the ordinary method are totally obviated .by our process of annealing, as when the protecting fiber is removed the castings come out with clean and smooth surfaces.

In the drawing, a represents a bar of caststeel, around which is packed the asbestos fiber 6, contained in the iron box 0, said asbestos fiber being first moistened to secure flexibility, and afterward tamped thoroughly in. The box 0 has perforations d d drilled in its walls to admit of a free circulation of air and escape of vapor. The box is then closed, and the whole introduced into the annealingfurnace, where it is allowed to remain for a period of, say, twenty-four hours, when it is withdrawn and allowed to cool, the process thereupon being completed.

A saving of time varying from seven to ten days is thus effected by the process of our invention over the methods heretofore in use.

Having thus described our invention,-'What we claim as new, and desire to secure by Letters Patent, is

The process of annealing metal castings,

which consists in enveloping the castings to be annealed in fibrous or finely-divided asbestos, which is tightly packed about the castings in a perforated or porous chamber or casing, the whole being exposed to an annealing heat and allowed to slowly cool, substantially as described.

In witness whereof we hereunto subscribe our names this 8th day of July, A. D. 1896.

JAMES EVETTS. FRANCIS O. SOHURZ. lVitnesses:

ELMER BISHOP, SELDEN FIsH. 

